Recombinant Mononucleosomes (H3.1) consist of a 167 bp of 601 DNA without any tag and two molecules each of histones H2A that includes amino acids 1-130 (end) (accession number NM_003512), H2B that includes amino acids 1-126 (end) (accession number NM_003518), H3.1 that includes amino acids 1-136 (end) (accession number NM_003529), and H4 that includes amino acids 1-103 (end) (accession number NM_003548). All of these histones were expressed in E. coli cells. The molecular weight of histone octamer is 108 kDa.